The invention relates to a static mixer with profiled layers and to uses of a mixer of this kind.
In static mixers fluids which flow through fixed installations are homogenized by these installations. There is a large variety of constructional forms. In most static mixers the installations are built in in the form of similar elements in a pipe or a channel. In this they are regularly arranged so that a homogenizing of the components which are to be mixed results over the entire pipe cross-section. Static mixers are also known in which the installations; are in each case arranged in a ring space between two concentric walls. In a review article with the title xe2x80x9cStatische Mischer und ihre Anwendungxe2x80x9d (M. H. Pahl, E. Muschelknautz; Chem.-Ing.-Techn. 52 (1980) No. 4, pp. 285-291) a mixer of this kind is described (FIG. 1e): A series of in each case four twisted baffle plates are secured alternatingly left-handed and right-handed on a cylindrical inner body.
A static mixer with a ring-space shape in which corrugated layers form a cross channel structure with inclined, openly crossing flow channels is known from EP-A 0 697 374. The layers are planar and parallel to a main flow direction.
There are tasks in connection with homogenizations of fluids, for the solution of which ring-space mixers present themselves particularly advantageous. One example: In drilling for petroleum and/or natural gas a drilling channel is produced in which a ring-space-like channel remains open between a jacket pipe and a drilling rod. Material which is set free in the boring head and which can comprise a fluid mixture of liquids (water, petroleum) and gases is conveyed in the axial direction through the ring space. At a depth and at a vertical distance from the deposits the advance of bores of this kind are as a rule turned round from the vertical direction into a direction in which the bore extends horizontally in the extreme case. A large number of bores of this kind are produced which radiate from a central bore toward the periphery of a field from which natural gas and/or petroleum is to be won. In the conveying of the materials to be won the individual bores as a rule yield material mixtures of differing quality. Monitoring devices are provided for monitoring the quality which can be pushed into the drilling channels down to the depth of the deposits. With the help of sensors in the monitoring devices the proportions of the phases (oil, water and/or gas) in the fluid mixture which flows through can be determined.
In order to ensure representative measurement results it is necessary in the monitoring of the quality for the different phases of the fluid mixture, which have different densities, to flow through the measurement regions of the sensors with a uniform distribution. Therefore static mixer elements are to be built into a homogenization region which is placed ahead of the monitoring device. Since phases of different densities segregate in a horizontal or inclined pipe, the static mixer must be formed in such a manner that a segregation of this kind is largely prevented or, if it has already set in, can be reversed. This property is largely lacking in the known ring-space mixers.
It is an object of the invention to create a static mixer for a fluid mixture which consists of phases of different density and which is to be transported in the axial direction through a ring space, with it being possible for the axis of the ring space to be horizontal or inclined.
The static mixer comprises profiled layers which are arranged in a ring space and which contain mutually crossing flow channels which are inclined relative to a central axis. A fluid mixture is to be transported in the axial direction in the presence of a mixing action. Each layer extends over a surface which forms a closed or largely closed periphery transverse to the axis. Each layer comprises equivalent channels which extend on an inner or outer side of the layer over at least approximately equally long distances from a first to a second cross-section of the ring space, so that each channel imposes an azimuthal velocity component onto the fluid mixture flowing through it which is substantially equally large for all equivalent channels.
In the following the invention will be explained with reference to the drawings.